There are many applications where wire, or other round, square or shaped profile rod or pipe, must be cleaned to remove rust, paint, scale, etc., to prepare the surface for subsequent processing. The techniques available for cleaning wire consist of batch and continuous processes. In a batch process the entire coil of wire is cleaned at one time. In a continuous process the wire is cleaned as it is fed off the coil. While both processes require a large amount of space, batch processes generally require more space. Extra material handling is also required with batch processes. The main techniques include acid cleaning, shot blasting, ultrasonic cleaning, grinding or mechanical methods.
Acid cleaning consists of using an acid, such as a sulfuric or hydrochloric acid solution, to dissolve the surface contaminate from the wire. This can be a batch process where the coil is immersed in an acid bath for five to twenty minutes or a continuous process where the wire is pulled through a trough that is filled with acid. This method will clean the wire very thoroughly. However, it is very expensive to build and to operate an acid cleaning system because of the safety and environmental hazards associated with handling acid. Also, the process must be carefully controlled so the wire itself is not dissolved.
Shot blasting consists of blasting the wire surface with abrasive media such as steel shot, sand or glass beads. This method can be a batch process where the entire coil of wire is put in a large blast cabinet or a continuous process where the wire is pulled through a small blasting chamber. With both processes, the wire is blasted either through multiple nozzles or by spinning wheels throwing the shot to clean the surface. The equipment used to blast wire is very expensive. Batch processing equipment is expensive to maintain as the process is inherently self-destructive. Also, it can be difficult to clean the entire circumference effectively. The continuous process has high operating cost because a large volume of compressed air or electrical power is required to propel the shot. It can also be a slow process.
Ultrasonic cleaning consists of pulling the wire continuously through an aqueous solution while the wire is subjected to ultrasonic vibrations which essentially cause the contaminate to implode from the wire surface. This equipment is expensive and currently can remove only limited types of contaminates. It can also be a slow process.
Grinding consists of using a series of grinders with abrasive wheels, made from wire or synthetic materials, which rub against the wire to clean it as it is pulled by in a continuous process. The system required to grind wire is cheaper than the above methods but is still relatively expensive. Also, it is particularly difficult to control both the pressure of the wheels against the wire and the wire speed so that the wire is cleaned thoroughly while not abrading the wire surface itself. The wheels must also be strategically placed so that they clean the entire circumference of the wire.
Mechanical methods consist of bending the wire in one or more U shapes to crack semi-brittle, hard-to-remove surface contaminates so the material can be more easily removed subsequently by another method such as grinding. This method can be relatively expensive. It is limited to wire which is fairly flexible and can tolerate the severe bends without breaking.
Abrasive media, such as sandpaper or synthetic pads or grids can effectively and economically remove scale, etc. from wire. However, if they are applied against the wire in a continuous process, they can plug with debris, lose their abrasiveness, and stop cleaning the surface effectively. The media then has to be removed, cleaned off, and reapplied. These maintenance requirements can make them impractical to use.
Accordingly, there remains a need for an economic, environmentally manageable solution for cleaning wire.
The present invention meets the above-described need by providing a relatively small block that is generally elongated and has an internal chamber. A port extends to the chamber from a side of the block and is connected to an air supply. A groove is made on one side of the block. The groove generally conforms to the wire diameter or shape. Holes are made from the bottom of the groove to the chamber. An abrasive media is placed over the holes in the groove on two of the blocks. A pair of the above-described blocks with the media in the grooves are placed on opposite sides of the wire and squeezed together by clamps, holding the media against the wire. The face on the leading side of the block is placed against a stop to prevent it from moving as the wire is pulled. Additional pairs of blocks are added as required in a radial direction to cover the entire circumference of the wire. As the wire is pulled, air is injected into the ports in the blocks. The air exits from the holes and blows off the debris from the media. The air may be continuous or intermittent. As a result an economical, relatively low maintenance system and method for cleaning wire has been achieved.